Rethinking early arthrogenic muscle inhibition after total knee arthroplasty

We read with interest the recent article by Barrera Uso et al. on early arthrogenic muscle inhibition (AMI) after total knee arthroplasty (TKA). The study provides clinically relevant evidence that AMI at 30 days strongly predicts persistence at 60 days. We suggest, however, that this finding should be interpreted as a prognostic association rather than evidence that 30-day AMI is the dominant biological determinant of subsequent inhibition. We also discuss the timing of postoperative assessment, noting that evaluation at 30 days is appropriate for studying persistence but less informative regarding the initial pathophysiological development of AMI. The Scientific Anterior Cruciate Ligament Network International (SANTI) classification has demonstrated excellent reliability in anterior cruciate ligament populations, although its generalizability to TKA remains to be specifically established. Finally, the absence of objective functional and patient-reported outcomes limits interpretation of the clinical significance of persistent AMI. Overall, the study identifies an important clinical phenotype and useful prognostic markers while leaving the underlying mechanisms of persistence to be further clarified.